A study of the physicochemical and immunologic properties, synthesis and metabolism of human and rat alpha-1 fetoprotein will be conducted to elucidate the function of alpha-1 fetoprotein in embryonic and fetal growth and development, and malignant transformation and growth. Alpha-1 fetoprotein isolated from fetal/newborn rat serum and amniotic fluid, hepatoma-bearing rat serum, human amniotic fluid and hepatoma-bearing human serum by a method developed in this laboratory will be analyzed for their carbohydrate and amino acid content, sedimentation properties, molecular weight, isoelectric point, quaternary structure, immunologic reactivity and unique antigenic determinants. The metabolism of I131-and I125- labeled fetal/newborn rat alpha-1 fetoprotein and hepatoma-bearing rat alpha-1 fetoprotein will be compared in newborn rats, in normal adult rats and in adult rats during liver regeneration, during induction of hepatomas and following acute injury. These studies will reveal if fetal and tumor alpha-1 fetoprotein have similar metabolic patterns and if alterations in the metabolism of alpha-1 fetoprotein occur during any of these physiologic states. Examining the metabolism by normal adult rats of alpha-1 fetoprotein radiolabeled with tritium-and carbon-14-labeled carbohydrate and amino acid will elucidate the metabolic rates of the oligosaccharide and polypeptide portions of the glycoprotein. Rat embryo culture studies will determine if the survival of the embryo is associated with synthesis and metabolism of alpha-1 fetoprotein. BIBLIOGRAPHIC REFERENCES: C.J. Smith and P.C. Kelleher. Concancvalin-A affinity alpha-fetoprotein molecular variants in fetal and hepatoma-bearing serum. Vermont Regional Cancer Center Symposium, Burlington, Vermont, Jan. 27-28, 1975. (Abstract). C.J. Smith and P.C. Kelleher. Letter to the editor, Re: A.I. Pick, et. al., Alpha-fetoprotein assay: Significance and clinical applications (August, 1975). New York State Journal of Medicine.